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Ammonium fluoride, NH4F, is often seen as an analog to ice, with several of its solid phases closely resembling known ice phases. While its ionic and hydrogen-ordered nature puts topological constraints on the ice-like network structures it can form, it is not clear what consequences these constraints have for NH4F compound formation and evolution. Here, we explore computationally the reach and eventual limits of the ice analogy for ammonium fluoride. By combining data mining of known and hypothetical ice networks with crystal structure prediction and density functional calculations, we explore the high-pressure phase diagram of NH4F and host–guest compounds of its hydrides. Pure NH4F departs from ice-like behavior above 80 GPa with the emergence of close-packed ionic structures. The predicted stability of NH4F hydrides shows that NH4F can act as a host to small guest species, albeit in a topologically severely constraint configuration space. Finally, we explore the binary NH3–HF chemical space, where we find candidate structures for several unsolved polyfluoride phases; among them is the chemical analog to H2O2 dihydrate. [ABSTRACT FROM AUTHOR]

Recently, a new gas hydrate structure has been discovered. This structure, sX, is unique in a sense that it is so far the only gas hydrate with chiral channels. It is formed by hydrogen-water or carbon dioxide-water mixtures at pressures above 0.300 GPa, and it has been shown that it is the only clathrate hydrate that is refillable with hydrogen. This property makes it a possible storage material for gases. By analyzing neutron diffraction data and calculations based on density-functional theory, we show that sX is also refillable with nitrogen; the guest:host ratio will be shown to be 2.6(3). Furthermore, we report sX's decomposition behavior and give evidence that it undergoes several transitions into the exotic hydrates sH and sIII that have not been observed at these pressure and temperature conditions—before forming the stable nitrogen hydrate sII. [ABSTRACT FROM AUTHOR]

We explored whether supported (SJE) or coordinated joint engagement (CJE) between mothers recruited from the community and their 24-month-old children who were slow-to-talk at 18 months old were associated with child language scores at ages 24, 36, and 48 months (n = 197). We further explored whether SJE or CJE modified the concurrent positive associations between maternal responsive behaviours and language scores. Previous research has shown that SJE, maternal expansions, imitations, and responsive questions were associated with better language scores. Our main finding was that SJE but not CJE was consistently positively associated with 24- and 36-month-old expressive and receptive language scores, but not with 48-month-old language scores. SJE modified how expansions and imitations, but not responsive questions, were associated with language scores; the associations were evident in all but the highest levels of SJE. Further research is necessary to test these findings in other samples before clinical recommendations can be made. [ABSTRACT FROM AUTHOR]

New product development ( NPD) has become a critical determinant of firm performance. There is a considerable body of research examining the factors that influence a firm's ability to successfully develop and introduce new products. Vital to this success is the creation and management of NPD teams. While the evidence for the use of NPD teams and the factors that determine their success is accumulating, there is still a lack of clarity on the team-level variables that are most impactful on NPD success. This meta-analytic study examines the effects of NPD team characteristics on three different measures of success: effectiveness (market success), efficiency (meeting budgets and schedules), and speed-to-market, requiring incorporation of a broader set of team variables than previous studies in order to capture more factors explaining NPD outcomes. Unlike a typical empirical study that considered no more than two team variables to predict NPD performance, this study combines research spanning eight team variables including team input variables (team tenure, functional diversity, team ability, and team leadership) and team process variables (internal and external team communication, group cohesiveness, and goal clarity). Results from 38 studies were aggregated to estimate the meta-analytic effect sizes for each of the variables. Using the meta-analytic results, a path analytic model of NPD success was estimated to isolate the unique effects of team characteristics on NPD effectiveness and efficiency. Results indicate that team leadership, team ability, external communication, goal clarity, and group cohesiveness are the critical determinants of NPD team performance. NPD teams with considerable experience and led by a transformational leader are more successful at developing new products. Effective boundary spanning within and outside the organization and a shared understanding of project objectives are paramount to success. Group cohesiveness is also an important predictor of NPD outcomes confirming the importance of esprit de corps within the team. The findings provide product development managers with a blueprint for creating high-performance NPD teams. [ABSTRACT FROM AUTHOR]

Background Pre-school language impairment is common and greatly reduces educational performance. Population attempts to identify children who would benefit from appropriately timed intervention might be improved by greater knowledge about the typical profiles of language development. Specifically, this could be used to help with the early identification of children who will be impaired on school entry. Methods This study applied longitudinal latent class analysis to assessments at 8, 12, 24, 36 and 48 months on 1113 children from a population-based study, in order to identify classes exhibiting distinct communicative developmental profiles. Results Five substantive classes were identified: Typical, i.e. development in the typical range at each age; Precocious ( late), i.e. typical development in infancy followed by high probabilities of precocity from 24 months onwards; Impaired ( early), i.e. high probabilities of impairment up to 12 months followed by typical language development thereafter; Impaired ( late), i.e. typical development in infancy but impairment from 24 months onwards; Precocious ( early), i.e. high probabilities of precocity in early life followed by typical language by 48 months. The entropy statistic (0.84) suggested classes were fairly well defined, although there was a non-trivial degree of uncertainty in classification of children. That half of the Impaired ( late) class was expected to have typical language at 4 years and 6% of the numerically large Typical class was expected to be impaired at 4 years illustrates this. Characteristics indicative of social advantage were more commonly found in the classes with improving profiles. Conclusions Developmental profiles show that some pre-schoolers' language is characterized by periods of accelerated development, slow development and catch-up growth. Given the uncertainty in classifying children into these profiles, use of this knowledge for identifying children who will be impaired on school entry is not straightforward. The findings do, however, indicate greater need for language enrichment programmes among disadvantaged children. [ABSTRACT FROM AUTHOR]

Nine ruminally cannulated mixed-breed steers were used in a split-plot design to evaluate effects of fat supplementation and forage maturity on intake, digestibility, and ruminal fermentation. Treatment was the main plot, and stage of forage maturity was the subplot. Treatments were supplements containing mineral pack (M) offered at 114 g/d; M plus fiber as soybean hulls-wheat middlings (MF) offered at 0.50% BW; and MF plus tallow (MFT) offered at 0.625% BW. Stages of wheat maturity were mid-March (MAR) and early April (APR). Steers grazed in a single wheat pasture with supplements offered individually at 0700 h daily. There were supplement type x forage maturity interactions (P < 0.05) for forage OM, CP, and NDF intakes. During MAR, forage OM, CP, and NDF intakes were not affected (P > 0.05) by supplementation. During APR, forage OM, CP, and NDF intakes differed (MF = M > MFT, P < 0.05). There was also supplement type x forage maturity interaction (P = 0.04) for forage OM digestibility. The OM digestibility differed during MAR (M = MF > MFT, P < 0.05) and during APR (MF > M > MFT, P < 0.05). Crude protein digestibility was affected by supplement type (M > ME > MFT, P < 0.05) and stage of forage maturity (MAR > APR, P < 0.01). Rates of DM and NDF ruminal disappearance were not affected (P > 0.05) by supplement or forage maturity. Supplementation increased (P < 0.05) ruminal propionate concentration (19.7, 21.4, and 25.1 ± 0.49 moI/100 mol for M, MF, and MFT, respectively). Tallow can be used in supplements for cattle grazing wheat pasture to increase energy intake without negatively affecting forage intake or ruminal fermentation, particularly if used in the early stage of wheat maturity. [ABSTRACT FROM AUTHOR]

Purpose - The purpose of this paper is to improve the capability of managers to forecast revenues and develop marketing plans for B2B component products. Design/methodology/approach - The methodology used is a dynamic market simulation at the product level. A previously developed consumer goods speciality product forecasting model is extensively modified to capture the different parameters (i.e. direct selling) relevant to a business-to-business (B2B) component goods product category. A dynamic simulation is developed using a set of equations developed to capture the marketing mix. Using just the demand equation (total supply exogenous) and employing the entire model (supply endogenous), sales are predicted. Findings - The key findings are that the simulation produced more accurate (lower error) forecasts. The dynamic simulation for total demand for B2B auto components produced a mean absolute percentage error (MAPE) of 8.5 percent, comparing favorably with the average MAPEs of 30 percent achieved by 168 companies forecasting B2B products. Research limitations/implications - The main research limitation is that the model is limited to B2B component products. Practical implications - The practical implication of the model is that it improves the ability of marketing managers to successfully reach revenue targets. Originality/value - This improved ability adds value to the B2B component marketing manager's planning process by providing a method of specifying a marketing plan that is likely to result in revenue that achieves or exceeds the target revenue and knowledge of what marketing mix levels would move present sales to meet or exceed target. [ABSTRACT FROM AUTHOR]

The article presents a study on whether high technology venture firms funded by the U.S. Department of Commerce Advanced Technology Program (ATP) pursue different types of marketing strategies and different goal levels than firms without such funding. The mission of ATP is to prevent the most promising new technologies with the greatest potential for widespread national benefits, from remaining in the research laboratory. ATP steps into the gap between the research laboratories and the marketplace by funding projects judged too risky or too far outside the mainstream to warrant private funding. The ATP provides cost-share funding in the high risk early stages of research and development that are prohibitive for other sources of funding.

Changes in oxygen consumption, ammonia excretion and in the acid-base and energy status of various tissues were investigated in the cold stenothermal Antarctic bivalve, Limopsis marionensis, and compared to similar data in the limpet, Nacella concinna, for an assessment of thermal sensitivity. Oxygen consumption of L. marionensis varied between −1.5 and 2°C with a Q10 of 2.2. Ammonia excretion could only be detected in animals exposed to elevated temperature for periods in excess of 45 days and close to death and it is interpreted as the onset of protein and amino acid catabolism with starvation under temperature stress. In L. marionensis any change in temperature as well as starvation stress at constant temperature induced a decrease in phospho- l-arginine and ATP levels. However, only temperature stress resulted in a drop in the Gibb's free energy change of ATP hydrolysis. Intracellular pH rose in all tissues during upward or downward temperature changes of only 1.5 or 2°C for 24 h with a concomitant trend to accumulate succinate and acetate in the tissues. These changes are seen to reflect disturbances of the tissue acid-base and energy status with any under- or overshoot in aerobic metabolic rate during a temperature decrease or increase. Elevated temperature at 2°C during 2 weeks of incubation resulted in continued net ATP depletion, at low levels of ATP free energy. This indicates long-term stress, which was also mirrored in the inability to establish a new steady-state mean rate of oxygen consumption. Incubation at even higher temperatures of 4 and 7°C led to an aggravation of energetic stress and transition to an intracellular acidosis, as well as a fall in oxygen consumption. In N. concinna a drop in energy levels was also visible at 2°C but was compensated for during long-term incubation. In conclusion, L. marionensis will be able to compensate for a temperature change only in a very narrow range whereas the thermal tolerance window is much wider in N. concinna. The inability of the metabolic rate to rise continually and the concomitant transition to anaerobic metabolism and long-term energetic stress characterize the upper critical temperature. Stenothermality is discussed, not only as reflecting the permanent and very stable low temperature in the natural environment, but also regarding dif- ferences in the level of activity and aerobic scope. [ABSTRACT FROM AUTHOR]

The effect of various carbon, nitrogen and sulfur sources on the production of heparinase by Flavobacterium heparinum in defined medium in the presence and absence of heparin as the inducer has been studied. Carbon catabolite repression has been observed in defined medium containing one of several carbon sources including simple sugars, alcohols and organic acids. Fed batch fermentations result in 10 g/l of cells and heparinase titers as high as 100,000 U/l by avoiding carbon catabolite repression. Growth on heparin as a sole carbon source resulted in both a high growth rate of 0.12 h and a high specific activity of 18 U/mg. Specific heparinase activity was markedly reduced when the end products of heparin catabolism were used as carbon, nitrogen or sulfur sources in defined medium. In defined medium with a low sulfate concentration, of less than 10 M, specific activities as high as 8 U/mg have been observed even in the absence of the normally required inducer, heparin. [ABSTRACT FROM AUTHOR]

Explores the economic development model by Irma Adelman. Approach used by several economists in dealing with the unemployment-subsistence problem; Significance of exogeneous parameters for the economic growth; Role of the government in the promotion of economic growth; Stages of economic growth.

Marketing managers competing with public enterprises face additional and unique problems compared with those which compete with other private firms. State and local government firms competing against private firms are granted a number of tax advantages over privately owned firms. Public firms can be less efficient, yet its price can be lower than the private competitor, often neutralizing price as a weapon in the marketing mix of the private firm in such a competitive milieu. An incentive exits to replace the private competitor with the less productive public one. Estimate herein of such competitive disadvantages for the private competitor in the electrical utilities, gas, water, and telephone industries provide the private marketing manage with a gauge of the disadvantage that must be overcome to compete effectively. [ABSTRACT FROM PUBLISHER]

Onions were preinfected with seven Endogone spore types and red clover with five spore types and then grown in P deficient, [sup32]P labeled soils. P uptake was much greater in most mycorrhizal plants than in controls. Specific activities of absorbed P were almost identical in all mycorrhizal and control plants. [ABSTRACT FROM AUTHOR]

No abstract available for this article. [ABSTRACT FROM PUBLISHER]

Cross cultural differentiation is found to be an important variable in improving the effectiveness of the promotion function of sales in industrial marketing. Four cultures (EU, US, Japan, and Latin America-LA) are compared in terms of Hofstede's (1984) cultural differentiation parameters. Substantial differentiation in line with Hofstede's parameters is required across cultures in the industrial sales function to generate effective marketing results. Rules and independence typifies German buyers, while flexibility and team consensus typifies US and Japanese buyers. [ABSTRACT FROM AUTHOR]

Examines the problem of improving accuracy in consumer product sales forecasting. Assistance in management planning; Prediction of annual revenues; Instrument for the marketing manager.

Examines the retail product line and total market sales forecasting models. Utilization of sales strategy via accurate forecasting; Capability of segment models in making inferences on price and advertising cross-price elasticities; Comparison on the accuracy of forecast and total market sales forecasting models.

This article compares the price implications of various models of price theory with the observed prices in a particular industry. The purpose of this comparison is to say something about the reliability of various models in predicting observed prices in a specific cost-demand environment. Empirical estimates of demand and cost relationships were made for the corrugated specialties industry from survey data of the three firms in the industry and their customers. Two types of industry demand curves can be derived. First buyers' intentions at various alternative prices may be ascertained at a point in time. These ex ante intentions correspond to theoretical demand curves. Second, the actual sales and prices can produce an empirical demand curve. This ex post approach involves a considerable number of problems with identification, which in turn makes estimates of equilibria subject to error. The expanded William Fellner model doesn't specify whether individual or joint profit maximization must take place, but only that a tendency to maximize joint profits be in effect. Specific prices and market shares are not specified and a relatively narrow pricing range results.

Modern rent theory evolved considerably from rent's classical definition as an unearned increment and rests today on the classical footing that part of rent enters price. Rent on marginal land arising from opportunity cost becomes a cost and affects pike. However, no synthesis could be made with the classical view of rentless margins with rent no part of price. Alfred Marshall developed Adam Smith's monopoly theory to where short run quasi-rent arises from fixed land supply, intro- ducing rent as a cost which may be price-determined. The diminishing returns theory followed Maithus' concept that when successive lands are cultivated, they are more and more inferior. The productivity theory of John Bates Clark integrated rent theory by defining rent as the dis- counted value of the marginal product of land. Land of equal quality and unlimited supply would have a zero marginal product and be rentless. Measurement of Clarkian rent has been developed through the Cobb- Douglas production function. Under perfect competition, rent will determine the efficient allocation of various lands ranked by their respective marginal products. Variance of tents around the marginal product of land stemming from the institutional frictions of imperfectly competitive conditions are measurable and represent extensions of the Clarkian theory into a modern theory of rent resting on classical footings. [ABSTRACT FROM AUTHOR]

Adam Smith considered rent a surplus which arises because some produce sells for a price in excess of the cost of production. Thus rent is price-determined rather than price determining. Thomas Malthus contributed the beginnings of the differential theory of rent, endeavoring to show that rent will not arise until land of inferior quality is taken under cultivation. David Ricardo fully developed the theory of rent which is named Ricardian: rent is a surplus in the form of a differential. Henry George brought the classical position to its logical conclusion: rent is an unearned increment. [ABSTRACT FROM AUTHOR]

Presents a comment to the paper "A Stable Price Adjustment Process," by Anjan Mukherji. Proposal of a price adjustment process that does not require knowledge of the Jacobian of the excess demand functions; Limitation of the informational requirements to prices and excess; Reliance of the theorem on assumptions.